This invention relates to a radio frequency (RF) power device.
It is known to provide RF power devices such as RF-LDMOS transistors and GaN-HEMT in an array on a semiconductor substrate.
Power devices of this kind generate a large amount of heat, which can lead to self heating and mutual heating between the devices in the array. This heating can lead to performance degradation or even transistor damage.
In an attempt to mitigate mutual heating of different transistors in the array, the transistors in known array designs are spaced apart by a given distance or pitch. The pitch used in practical devices is known to be 50-150 μm, whereas the size of the transistors themselves may be much smaller (e.g. 3-15 μm). The space in between the transistors represents a large amount dead space on the substrate in which the RF power device is provided.
Power transistors typically have a low input and output impedance. Accordingly, for certain applications, these power transistors are coupled to impedance matching circuits. These impedance matching circuits typically comprise components such as inductors and capacitors.